1. Field of the Invention
This patent relates to a pressure-activated flexible valve for use with a container for dispensing fluid material. More particularly, this patent relates to a pressure-activated flexible valve attachable to a printing ink cartridge that automatically opens and closes in response to pressure from the ink.
2. Description of the Related Art
Modern ink cartridges for printing presses typically comprise a hollow tubular body, a moveable plunger inserted into one end, and a stationary dispensing fitment attached to the opposite end. The dispensing fitment covers the dispensing end of the tubular body and also serves as a valve for opening and closing the cartridge. Ink is extruded from the cartridge when the plunger is forced toward the dispensing end either manually or, more commonly, by pneumatic pressure.
The valve or dispensing fitment is mounted in sealing engagement within the dispensing (top) end of the tubular body. The valve serves four functions: (1) It controls the flow of ink from the cartridge when the plunger is activated. (2) It prevents the flow of ink at all other times, including during filling, transportation, storage, and installation of the cartridge on the printing press. (3) It prevents the introduction of air into the cartridge, which can cause localized ink drying at the nozzle and can effect the properties of the ink contents through oxidation or changes in viscosity. (4) It prevents the flow of ink to other areas of the dispensing fitment or printing equipment. (Ink found in these areas can dry and flake off, contaminating the ink reservoir.)
One known ink cartridge valve is that disclosed in Ritter European Patent Document EP 1 005 999 A3. The Ritter valve is equipped with integrally formed elastic wall stays that serve as springs to open and close the valve in response to pressure exerted by the cartridge contents.
Ritter discloses a valve comprising a central body having a dome-shaped sealing portion connected to the inside of the neck of a mouthpiece by bridges, and a valve sleeve mounted over the neck. The valve sleeve has an annular lip that mates with the sealing portion of the central body to close the valve. The valve sleeve is equipped with the integrally formed wall stays that serve as springs. The wall stays stretch in the axial direction when the valve is subjected to internal pressure from the ink, which raises the annular lip, creating an annular opening between the sealing portion and the valve sleeve lip.
Unlike the present invention, the Ritter valve has two moveable sealing surfaces. A first sealing surface is found at the interface of the central body sealing portion and the annular sealing lip. This sealing surface controls the flow of ink out of the cartridge. A second sealing surface is found at the interface of the mouthpiece neck and an annular valve sleeve wiper. This sealing surface is intended to prevent ink from leaking past the mouthpiece neck and into the area around the spring-like wall stays. These sealing surfaces must be manufactured to very tight tolerances and are subject to damage prior to and during assembly.
Thus it is an object of the present invention to provide a dispensing valve for dispensing fluid materials that has only one sealing surface.
Yet another object of the present invention is to provide a valve that is activated by the internal pressure of the container.
Further and additional objects will appear from the description, accompanying drawings, and appended claims.
The present invention is a pressure-activated valve for use with a container for dispensing fluid material. In a preferred embodiment, the valve comprises an outer component and an inner component. The outer component comprises a covering portion and a nozzle mounted on the covering portion. The nozzle has a substantially cylindrical sidewall, a top edge, and an annular flexible portion extending radially inward from the top edge of the sidewall and terminating in a rigid annular rim.
The inner component comprises a sidewall and a stationary sealing portion connected to the sidewall via bridges. The inner component is affixed to the inside of the nozzle sidewall and mates closely therewith. The sealing portion and the rigid annular rim of the outer component cooperate to form a seal when the valve is in the closed position. When the valve is in the open position, the sealing portion and annular rim define an annular opening through which the fluid material may flow.
In a key aspect of the invention, the annular flexible portion of the outer component is configured to flex upward and outward when subjected to sufficient pressure from the container fluid material, thereby moving the rigid annular rim between a closed position to an open position. In the preferred embodiment, the flexible portion has a substantially S-shaped cross-sectional profile.
In an alternative embodiment, rather than extending inward from the top edge of the nozzle sidewall, the flexible portion forms part of the nozzle sidewall and works like a bellows by expanding and contracting in response to changes in the container internal pressure. When the container internal pressure is below a certain level (i.e. when the flexible portion is in the contracted position), the rigid annular valve rim of the outer component seats against the convex sealing portion of the inner component to close the ink cartridge and prevent the flow of ink. When sufficient pressure is exerted on the valve by the container contents, the flexible portion expands, exposing an annular opening between the valve rim and the sealing portion, which allows the flow of ink out of the cartridge.
In a third embodiment of the invention, both the nozzle sidewall and the annular portion extending inward from the top edge of the nozzle are flexible. When sufficient pressure is exerted on the valve by the container contents, the nozzle sidewall and/or the annular portion flexes, exposing an annular opening between the valve rim and the sealing portion, which allows the flow of ink out of the cartridge.
In a fourth embodiment of the invention, the stationary sealing portion is attached directly to the container, and a substantially cup-shaped outer component having a flexible portion for opening and closing the valve is mounted onto the sealing portion.